Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transfusion of RBC units, the only current treatment for many myelodysplastic syndromes, and excess intestinal absorption of Fe related to dyserythopoiesis often result in iron overload. This condition is associated with high rates of morbidity and mortality. High-risk patients include those with refractory anemia, sideroblastic anemia, 5q-syndrome, patients with a good prognosis (low or lower intermediate international prognosis score), patients having received over 100 RBC units, and patients under the age of 70. Deferoxamine, while it can prevent iron overload, is a strenuous treatment requiring 8-to-12 hour-overnight subcutaneous injections. When patients comply with the regimen, it efficiently prevents mortality due to iron overload, but must be implemented early in the disorder, usually before transfusing 20 RBC concentrates. A simple way of monitoring iron overload is to measure seric ferritin levels and record the number of RBC concentrates. The chelating treatment should be modulated according to age, MDS type, international prognosis score, number of RBC units received, ferritin levels, and most of all, patient tolerance. The direct subcutaneous approach is currently being evaluated by the French Group for Myelodysplasias for its efficiency to prevent disorders, but seems to be both efficient and well complied with (a national protocol is under way). The recent findings on the proteins implied in iron recycling by macrophages after destruction of RBCs, may in the long term, enable us to manage patients with less burdensome treatments and more effective new oral chelates.
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PMID:[Iron overload and myelodysplastic syndromes]. 1172 96

Nitric oxide (NO) is a signaling molecule that plays a critical role in the activation of innate immune and inflammatory responses in animals. During the last few years, NO has also been detected in several plant species and the increasing number of reports on its function in plants have implicated NO as an important effector of growth, development and defense. Analogously to animals, NO has been recently shown to inhibit tobacco aconitase. This suggests that NO may elevate free iron levels in the cells by converting tobacco cytoplasmic aconitase into a mRNA binding protein that negatively regulates accumulation of ferritin. We investigated the possible role of NO as a regulator of ferritin levels in Arabidopsis and found that the NO-donor sodium nitroprusside (SNP) induces accumulation of ferritin both at mRNA and protein level. Iron is not necessary for this NO-mediated ferritin transcript accumulation, since SNP is still able to induce the accumulation of ferritin transcript in Arabidopsis suspension cultures pre-treated with the iron chelants DFO or ferrozine. However, NO is required for iron-induced ferritin accumulation, as the NO scavenger CPTIO prevents ferritin transcript accumulation in Arabidopsis suspension cultures treated with iron. The pathway is ser/thr phosphatase-dependent and necessitates protein synthesis; furthermore, NO mediates ferritin regulation through the IDRS sequence of the Atfer1 promoter responsible for transcriptional repression under low iron supply. NO, by acting downstream of iron in the induction of ferritin transcript accumulation is therefore a key signaling molecule for regulation of iron homeostasis in plants.
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PMID:Nitric oxide mediates iron-induced ferritin accumulation in Arabidopsis. 1204 27

Iron, through its participation in reactions that generate reactive oxygen species, may contribute to the oxidative lung injury observed in patients with acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS). A number of investigators have shown that the endogenous iron storage protein ferritin increases in the blood of patients with and at-risk for ALI and ARDS, but the significance of these increases are not known. In the present investigation, we measured lung tissue levels of thiobarbituric acid reactive substances (TBARS) and lung leak in isolated rat lungs perfused with xanthine oxidase (XO) and purine, an enzymatic system which generates reactive oxygen species. We found that adding ferritin (100 ng/mL) or desferrioxamine (DFO, 10 mM), an iron chelator, to the vascular perfusate solution decreased oxidant-induced leak in isolated rat lungs perfused with XO and purine. Addition of ferritin or DFO also decreased TBARS in isolated rat lungs perfused with XO and purine; neither ferritin nor DFO, however, decreased XO activity in vitro. Our results suggest that oxidative lung leak may be altered by the availability of reactive iron and that ferritin may contribute to protection against oxidative lung injury.
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PMID:Ferritin and desferrioxamine attenuate xanthine oxidase-dependent leak in isolated perfused rat lungs. 1218 28

Desferrioxamine (DFX) alone (40-50 mg/kg/d s.c. over 8-12 h, five times weekly) was compared with combined DFX twice weekly and deferiprone (75 mg/kg/d) over 12 months in previously poorly chelated thalassaemia patients. Serum ferritin fell from 5506 +/- 635 microg/l (mean +/- SEM) to 3998 +/- 604 microg/l (P < 0.001; n = 14) in the DFX group and from 4153 +/- 517 microg/l to 2805 +/- 327 microg/l in the combined group (P < 0.01; n = 11). Deferiprone plus DFX produced a greater mean urine iron excretion (1.01 mg/kg/24 h) than iron intake from blood transfusion in each patient. Main side-effects were skin reactions (DFX alone), nausea and arthralgia (combined therapy). As chelation therapy, the combined protocol was as effective as DFX five times weekly.
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PMID:Comparison between desferrioxamine and combined therapy with desferrioxamine and deferiprone in iron overloaded thalassaemia patients. 1267 Mar 52

The purpose of this study was to evaluate if the variations of heart magnetic resonance imaging in beta-thalassemia major patients treated with Deferoxamine B mesylate (DF) or Deferiprone (L1) chelation therapy is a useful tool of the indirect myocardial iron content determination. For this reason, a prospective study was carried out. Seventy-two consecutive patients with beta-thalassemia major (35 treated with DF and 37 with L1) were studied. The main outcome results were laboratory parameters including determination of the liver iron concentration (LIC) and magnetic resonance imaging (MRI) of the heart and liver. The heart to muscle signal intensity ratios (HSIRs) were significantly increased in both the DF (t = -2.8; p < 0.01) and L1 (t = -3.1; p < 0.01) groups after one year of treatment No statistically significant difference in the values of HSIRs was present between the two groups at the beginning of treatment (p = 0.25; t = 1.13), and after one year of treatment (p = 0.20; t = 1.28). The HSIR were inversely correlated to the LIC (r = -0.52; p < 0.001) but not with ferritin levels (r = 0.10; p = 0.18). A positive correlation was found between the variation of HSIRs and that of the liver signal intensity ratios (r=0.52; p < 0.001), and a mild correlation (r = 0.40; p < 0.001) was found between the gamma glutamyltransferase (gammaGt) levels and the HSIRs values. Our data confirm that heart MRI is sensitive enough to detect significant variations of the mean HSIR during iron chelation with DF or L1.
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PMID:Potential myocardial iron content evaluation by magnetic resonance imaging in thalassemia major patients treated with Deferoxamine or Deferiprone during a randomized multicenter prospective clinical study. 1500 64

The differential ferrioxamine test is a simple method for the measurement of chelation of body iron by desferrioxamine. A single six-hour specimen of urine is obtained after intravenous Desferal, accompanied by (59)Fe-ferrioxamine. Two values are measured: F(d), the excretion of ferrioxamine derived from body iron by chelation, and F(ex), the proportion of ferrioxamine excreted from a known intravenous dose. The data enables F(v), chelation of iron in vivo, to be calculated by simple proportion. Desferrioxamine chelation proceeds for about half an hour after injection. The results in normal subjects, in cases with known high iron stores, and in cases of iron-deficiency anaemia are described. High, normal, and low body iron states have been differentiated. F(v) values in the higher ranges obtained in iron-storage diseases and in haemolytic states are differentiated by the pattern of excretion, high F(d) values and low F(ex) values respectively. IT IS SUGGESTED THAT THERE ARE TWO MAIN SOURCES OF CHELATABLE BODY IRON: as ferritin-haemosiderin and as iron newly released from haem in a more readily chelatable form. The significance of variable chelation susceptibility in iron metabolism is briefly discussed. It is suggested that variable chelatability of different sources of body iron may explain the preferential utilization of iron released from red cells or absorbed from the intestine, rather than storage iron, in the biosynthesis of haem.
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PMID:DIFFERENTIAL FERRIOXAMINE TEST FOR MEASURING CHELATABLE BODY IRON. 1424 11

The dissociation of apoferritin into subunits at pH 2 followed by its reformation at pH 7.4 in presence of Desferrioxamine B (DFO) gives rise to a solution containing three DFO molecules trapped within the apoferritin (Apo-ferritin:DFO) and DFO molecules outside it. The untrapped DFO molecules in the solution were removed from Apo-ferritin:DFO by exhaustive dialysis until a negligible concentration was confirmed. The addition of Fe(III) to the dialyzed solution of Apo-ferritin:DFO resulted in the appearance of an orange-red color. The UV-Vis spectrum of this solution shows the characteristic absorption of the [DFOFe] complex centered at 425 nm. Following a similar procedure as for DFO, only one molecule of [DFOFe] was trapped in the apoferritin. The above results demonstrate the possibility of encapsulating a large molecule such as DFO in the apoferritin and, more interestingly, the ability of these DFO-encapsulated molecules to react with Fe(III) to give rise to an encapsulated [DFOFe] complex within the apoferritin.
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PMID:Iron(III) complexation of Desferrioxamine B encapsulated in apoferritin. 1498 47

In Parkinson's disease (PD) and its neurotoxin-induced models, 6-hydroxydopamine (6-OHDA) and N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), significant accumulation of iron occurs in the substantia nigra pars compacta. The iron is thought to be in a labile pool, unbound to ferritin, and is thought to have a pivotal role to induce oxidative stress-dependent neurodegeneration of dopamine neurons via Fenton chemistry. The consequence of this is its interaction with H(2)O(2) to generate the most reactive radical oxygen species, the hydroxyl radical. This scenario is supported by studies in both human and neurotoxin-induced parkinsonism showing that disposition of H(2)O(2) is compromised via depletion of glutathione (GSH), the rate-limiting cofactor of glutathione peroxide, the major enzyme source to dispose H(2)O(2) as water in the brain. Further, radical scavengers have been shown to prevent the neurotoxic action of the above neurotoxins and depletion of GSH. However, our group was the first to demonstrate that the prototype iron chelator, desferal, is a potent neuroprotective agent in the 6-OHDA model. We have extended these studies and examined the neuroprotective effect of intracerebraventricular (ICV) pretreatment with the prototype iron chelator, desferal (1.3, 13, 134 mg), on ICV induced 6-OHDA (250 micro g) lesion of striatal dopamine neurons. Desferal alone at the doses studied did not affect striatal tyrosine hydroxylase (TH) activity or dopamine (DA) metabolism. All three pretreatment (30 min) doses of desferal prevented the fall in striatal and frontal cortex DA, dihydroxyphenylacetic acid, and homovalinic acid, as well as the left and right striatum TH activity and DA turnover resulting from 6-OHDA lesion of dopaminergic neurons. A concentration bell-shaped neuroprotective effect of desferal was observed in the striatum, with 13 micro g being the most effective. Neither desferal nor 6-OHDA affected striatal serotonin, 5-hydroxyindole acetic acid, or noradrenaline. Desferal also protected against 6-OHDA-induced deficit in locomotor activity, rearing, and exploratory behavior (sniffing) in a novel environment. Since the lowest neuroprotective dose (1.3 micro g) of desferal was 200 times less than 6-OHDA, its neuroprotective activity may not be attributed to interference with the neurotoxin activity, but rather iron chelation. These studies led us to develop novel brain-permeable iron chelators, the VK-28 series, with iron chelating and neuroprotective activity similar to desferal for ironing iron out from PD and other neurodegenerative diseases, such as Alzheimer's disease, Friedreich's ataxia, and Huntington's disease.
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PMID:Ironing iron out in Parkinson's disease and other neurodegenerative diseases with iron chelators: a lesson from 6-hydroxydopamine and iron chelators, desferal and VK-28. 1510 75

With the introduction of "hypertransfusion" regimens the extent of disease- and therapy-related hemosiderosis has become the survival limiting factor for patients with beta-thalassemia major as iron transferred with transfusions cannot be excreted by physiological means. Subsequent introduction of deferoxamine therapy for iron elimination and prophylaxis of hemosiderosis has improved prognosis and life quality of these patients considerably. We report our experience with seven adolescent patients with beta-thalassemia and ineffective subcutaneous therapy and severe hemosiderosis-related organ complications. For that reason they received i. v. intensified chelate therapy. The patients were given 70 to 120 mg/kg DFO 7 days a week continuously via a Port-a-cath or Hickman central venous line. Under high-dose i. v. DFO therapy, serum ferritin levels significantly decreased in all patients. Target serum ferritin levels of 3 000 ng/ml were reached after 12 to 20 months of treatment. In 3 of the 5 patients that were treated for longer than 43 months serum ferritin levels even dropped below 2 000 ng/ml. Serum ferritin levels also correlated well with SQUID examinations. Therefore, monitoring of serum ferritin may be useful to monitor patient's compliance and control intensified DFO therapy. Continuous administration of the intensified DFO therapy induced normalization of liver function and left ventricular cardiac function in all patients who are still alive. Two patients died due to cardiac decompensation. In five patients 19 episodes of central catheter-related infections were observed (1.5 infections per 1 000 catheter days). No DFO-associated allergic reactions nor irreversible organ dysfunction were observed. Our results indicate that intensified i. v. DFO therapy is an effective and safe method for treatment of severe organ dysfunction in patients with thalassemia major. The most severe problems are catheter-related infections and inconsistent long-term compliance.
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PMID:Intensification of chelating-therapy in patients with thalassemia major. 1585 2

The introduction of apo-ferritin or the iron chelator DFO (desferrioxamine) conjugated to starch into the lysosomal compartment protects cells against oxidative stress, lysosomal rupture and ensuing apoptosis/necrosis by binding intralysosomal redox-active iron, thus preventing Fenton-type reactions and ensuing peroxidation of lysosomal membranes. Because up-regulation of MTs (metallothioneins) also generates enhanced cellular resistance to oxidative stress, including X-irradiation, and MTs were found to be capable of iron binding in an acidic and reducing lysosomal-like environment, we propose that these proteins might similarly stabilize lysosomes following autophagocytotic delivery to the lysosomal compartment. Here, we report that Zn-mediated MT up-regulation, assayed by Western blotting and immunocytochemistry, results in lysosomal stabilization and decreased apoptosis following oxidative stress, similar to the protection afforded by fluid-phase endocytosis of apo-ferritin or DFO. In contrast, the endocytotic uptake of an iron phosphate complex destabilized lysosomes against oxidative stress, but this was suppressed in cells with up-regulated MT. It is suggested that the resistance against oxidative stress, known to occur in MT-rich cells, may be a consequence of autophagic turnover of MT, resulting in reduced iron-catalysed intralysosomal peroxidative reactions.
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PMID:Metallothionein protects against oxidative stress-induced lysosomal destabilization. 1623 25


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